BMW i3 vs Cadillac CTS – Impact Results

Yesterday I was rear ended by a driver who sped through a stop sign and apparently didn’t notice me in front of him. His Cadillac hit me so hard I ended up 175 feet from the point of impact.

The impact was so hard that the center console arm rest flipped straight up and broke the latch. My seat back was even bent with the rear cover popping off. So a violent crash to say the least. But with no broken bones or cuts, this could have been much worse for me. They took away the passengers in the Cadillac by ambulance also, but there condition is still unknown at time of press, though obviously their airbags deployed.

Cadillac CTS after impact

Remarkably, the BMW doors all open and shut normally. Even the rear hatch released with the remote and closed normally.

While lying in the ambulance, I heard the first responders saying “I can’t believe how bad the Cadillac looks compared to that BMW!”

A testament to the safety engineering that went into the BMW i3. Kind of sad this happened to my BMW which was less than 2 months old with 1600 miles on the odometer; and I don’t look forward to the hassle of dealing with the other driver’s insurance company to get me on the road again.

Editor’s Note: Out of some concern we did follow up with Warren today when we heard this news, just to check in on his status, and he reported back he was A-OK

“…im okay. Ambulance was a precaution because of sore neck, ankle, and elbow. Did a cat scan at the hospital, nothing was broken. Took some muscle relaxant at the hospital and pain medicine. Feared I would feel horrible when waking up this morning, but okay. I plann on taking it easy for the rest of the weekend to make sure the aches and pain go away. Considering how light the i3 BEV is compared to a CTS, it fared pretty well.”

My i3 ended up 173 feet from the point of impact

Spot where the Cadillac came to rest

The violent force bent the seat back and dislodged the seat back cover. Center armrest went straight up, with the lid latch broken

As is often the case, Warren’s most recent modification on the car, a nifty rear bumper modification (which you can read about here), appears to have taken the brunt of the impact.

BMW looks very intact .. the cadillac not so much..there is a difference between crumble zones & aluminum foil..The cadillac needs the crumble zones Beefed Up some. There is TOOOO Much Un-necessary Give…

The right amount of give is the maximum amount that reduces the impact to the passengers, while not intruding into the passenger area. What part of the crumple that you see do you think is unnecessary? Do you honestly think that it should have crumpled less, thereby injuring the passengers more? Why?

First, hope the other driver is okay. Second, I’m interested in how the i3 absorbs impact and keeps that energy from harming the driver. In this case it was, perhaps, better that it bounced instead of crumpled, but had there been a car in front of the i3, I’m concerned about how the driver would fare vs. a more conventional car.

The author said that the rear hatch still functions. I believe it’s repairable. The Caddy, probably not. Hopefully all the occupants will be OK. We are not very repairable. Injuries do come back to haunt you as we age.

I think NHTSA and NCAP make a major mistake when testing front crashes by not including a test in witch the care is braking for the last seconds. The reason for this kind of test is that the car performs different when braking, the front of the care is leaning and the back is getting higher. the center of gravity is shifting forward in this way putting more stress on different components. I have been involved in such a crash and none of the safety features worked except for seat belts. No airbag deployed when I rear ended a car because that car had a shorter braking distance then my car. The damage to my car was extensive but only over the bumper (grille, headlamps, hood, fenders). The other car was an SUV with a bigger ground clearance them my car, the damage to the other car was located only in the lower and underneath the rear bumper aria. The SUV was braking too at the moment of the crash and it was leaning forward with the back higher then normal when I rear ended it. I think if the crash happened at greater speed in the same condition I… Read more »

I wish I could have seen this in slow motion. But who knows, perhaps the CTS was almost scooping the i3 up from below, and perhaps briefly lifted the car up. This is where a low cg, from having the battery pack on the bottom could keep the car from tumbling. There are some broken smaller carbon fiber pieces, so perhaps this might be more costly to fix than anticipated. Apparently it has to go to a special certified repair facility. So will be a while before I get any hard estimates.

This is also a reason you need GAP insurance. The insurance company might often try to just pay the cars blue book value, leaving you exposed to the amount owed to the bank. But since it was his fault, I might have to get an attorney if they make it impossible to restore me back to pre-accident condition.

Warren, I design, build 3wh, 1 rear wheel cars and was reared ended at 25mph built out of epoxy/plywood.
But it was designed to raise up letting the car slide under me with little damage and only cost me $40 to rebuild.
The compact car though was totaled as my main center beam went right through their radiator, etc.

Which driver? If you mean Warren, the violent impact would have thrown him backward — note the damage to the seat — which would have removed his foot from the brake pedal. So yeah, that’s why the car rolled 175 feet; there probably wasn’t any braking involved after the impact.

That’s not just physics; I write from my own experience when the car I was driving was rear-ended.

Well it’s a composite… Plastics (yes most (all) plastic is polymer…) can have very very very differing properties… They can be stretchable (think household foil for food) and can be brittle (think Plexiglas) heck they can even have differing modules of deformation for different axes (quite high tech) furthermore their properties change extremely depending on how far they are from glass transition temperature. I won’t start to talk about additives and side effects…

Carbon fibre also has different modules of deformation for different axes. Different fibre strengths can be used. Different geometry of fibre grid also has an influence…

I doubt anyone here has deep enough insight into the exact composition of that composites BMW uses to make any claim about the physical properties.

To put it simple: BMW (or the company which developed the composite) did a good job to protect Warren. That’s the one thing that matters.

It looked like the Caddy was braking hard and slid under the i3 a bit. That would explain the (1) long distance to stop [with only 2 wheels on the ground (2) rear window not being shattered (3) relatively small amount of damage to the fascia of the rear bumper. There could be a lot more damage to the underside of the i3, especially if it was a REx.

PP, if you knew how it was built you’d know the alum frame took most of the forces.
CF is more brittle and personally as a composite expert I wouldn’t use it in cars.
Instead FG and Kevlar like reinforcement fibers and lots of foam are much better in a crash, weigh and costs less.
Will, it is a polymer resin as most if not all plastics are.
Fact is 1/3 of the CF is in nylon like plastic in the i3.

franky,, Frankly I’ve been at it longer than they have with 50 yrs of composite vehicle design, and production.
Fact is compared to what I normally build, a car is a small lightly loaded vehicle.
For instance no reason BMW couldn’t build the i3 in 1500lbs or so if they left off the overweight alum frame/batterybox and crash structures.
Designed right there is no need for the alum as composites can handle all loads better designed right at 60% of the weight, cost.
And they are corporate engineers driven by fear and not great bosses doing some things the corporation doesn’t want to do, composites and EV’s.

Nice, but very disconcerting that the i3 ended up 175 ft from the point of impact. I think that’s mainly why it faired so well. It’s lighter so it basically got pushed away instead of crumpling. It’s a good thing it wasn’t pushed into a busy intersection or in front of a train…

Do not be deceived folks, the picture does not reveal the whole story here. Having worked with carbon fiber and fiber glass and aluminum on aircraft for years as a structural mechanic (Coast Guard) not all damage shows immediately. Think for a moment if you will if you slide an aluminum can into the back of a big wet sponge with force. Both are going to give depending on the impact but how much energy travels away from the initial impact area and how much will the materials spring back to their original shape is different, and as we see here BOTH systems did their job well –Protect the occupants at all cost. Yes the caddy looks bad, it is supposed to, remember save the people not your pride. The Beemer’s carbon fibers are broken I guarantee but they will snap back sometimes close to the original position but still be broken. Reason for replacing a “skid lid” following any cycle accident (peddle or motor) because not all damage is visible. Good thing most of the energy was dissipated on the rear end and did not travel and split the car into sections like the “good ol days” and spill… Read more »

I’m confused about the drivers thoughts of dealing with the other insurance company? I don’t know about the US, but here in Australia, as long as you are insured, you would only make acclaim with your own insurance company and then they will chase it all up, isn’t that what your paying for???? It doesn’t even matter if they are in-I sired, your car gets fixed, and your insurance will spend time suing them.

Not quite, not even in Oz, AFAIK from renting there.
You can submit a claim to your own insurance company, as you suggest, only if you have comprehensive insurance, but that’s not a legal requirement anywhere I’m familiar with.

Most countries/states require only 3d-party medical liability (that is, damage to other drivers/passengers/pedestrians/cyclists), sometimes also 1st-party medical (damage to you) and, rarely, also 3d-party property damage, but that wouldn’t cover damage to the car itself.

Now most likely Warren does have comprehensive, since the i3 is a somewhat expensive, new, car.
However, all car insurance policies I’ve ever encountered raise rates by quite a bit in case of any accident-related claim (no matter who was at fault), or have a hefty deductible (over here it’s typically $500-$1000), usually both. That means that at the very least one should consider making a claim against the at-fault driver and/or his/her insurance, before submitting a claim to one’s own.

Things happen so quickly, you barely have time to react. But for being hit slightly offset, it is a miracle the i3 stayed stable and didn’t dart off the road into a tree. I mean, you see how easily a pit maneuver can throw a car off line. To be hit like this and go straight down the road is really impressive, or lucky. This also is a reminder not to leave loose items such as laptops, tools, etc. The amount of G forces from even a 30mph impact is so tremendous, even a 1.5lb book can kill you. Tools can go through your seat. And most importantly realize, you can be stopped at an intersection, etc. You just never know when you can be the victim of a rear end impact. I have an old 1984 Civic S hatchback on the side of my house. 1970lbs. I can honestly say the Cadillac would have demolished it in the same situation.

All this shows is that the i3 doesn’t have a rear crumple zone. If it had been reversed, the Caddy would not have been tossed hundreds of feet out. Instead, it would have taken the damage in the rear. That’s what cars are supposed to do. Cars that maintain their shape the way the i3 did in this crash will result in drivers turning to goo on the inside if the crash is more severe.

If the Caddy weighed nearly 1000lbs less than the car rear ending it, it would definitely be tossed forward. The rear end of a hatch back has minimal crush room to begin with. There is no long trunk space. If you have children in the back, the last thing you want is cabin intrusion from crumpling. I have seem hatch backs fold from getting rear ended, and occupants trapped in side because the doors won’t open. Contrary to believe, the drivers side looks remarkably well to, with just the quarter panel unclipped from the upper rear area. The deformation occurred behind the lower bumper cover area, just as BMW designed it.

Thanks, Warren. I hope you are doing well. I have had many times when my ACC cut out. Once going 65 mph with a car behind me. I love my i3, but I believe that the ACC is too dangerous to use at high speeds. One guy reported that he had the same thing happen with the CC even though my BMW dealer said that would not happen. Bottom line, I love 98% of my i3, but will not use ACC at high speeds when the sun is out which is often here in Las Vegas. 🙂

Warren, great to see you’re OK, like Tom said above – truly what is most important.

There is innuendo here that the i3 was super tough, and it seems it’s structure did work for such a small car to retain it’s shape with doors opening. In a rear end collision there is not closing speed of two cars heading towards one another combined. This helps a lot, especially – as others have said, in a situation where the small car has no large crumple zone. I think both cars worked as designed – to the benefit of you all.

Warren – keep us posted on the end result to your i3. In other words, the cost of repair or if your car was a total in the eyes of your insurance company.

As Pushmi said – the force of impact pushed Warren and his seat back, bending the seat and lifting his foot off any pedals. This was a good thing – and a good thing nobody was in front of Warren, causing a chain reaction pileup. This allowed Warren’s i3 to be punted forward a long way! This is better than hitting a stationary object that doesn’t move, it’s a “smack”, rather than a “smash”, if that makes sense. A 2014 CTS is 4072 lbs. with V-6, compared to the i3’s 3571 lbs. as BEV/ 3813 with ReX. So if the driver in front can avoid a neck or spinal injury, it can be seen how this could have turned out worse in different circumstances, i.e.- more speed and/or car in front stuck in traffic. Smaller car = smaller crumple area = more shock on impact. It makes one ponder the upcoming Bolt EV. Similar or slightly smaller car – Honda Fit sized, with not a whole lot of space between rear “bumper” ( if you can call those bumpers ) and rear passenger area. Me? I like crumple zones. The sheer space allows for a progressive absorbtion of the crash… Read more »

Protecting the safety shell is the main priority in a small hatchback with minimal crunch space. Think of the Smart Car TRIDION safety cage. Incredibly strong and stiff for a good reason. The don’t want that cage to crush at all costs. Protect the occupants inside with the usual measures. The i3 has knee air bags, front airbags, side head curtains, etc. In addition. the car is big and open inside. Your knees aren’t even close to the dash. You can’t even reach the windshield far in front of you. These are all parts of the safety design elements the engineers planned into the car. Also, the i3 is nowhere near 3571 lbs. That is heavier than a LEAF! It also has close to the ideal 50/50 weight distribution. Here is a quote from the Car And Driver test results in its comparison with the B Class: “carbon fiber shows off the radical structure of the car: a composite cabin sitting atop a welded-aluminum skateboard chassis. It’s also apparent on the scales, where the i3’s 2853 pounds undercut the B-class by more than a half-ton. BMW has placed the heavy battery low and at the center of the car with… Read more »

This is “Jake” from state farm. Please tell the readers how your car really held up in this accident. I believe your car is totaled. Those pictures are completely misleading and you know it. Please provide an additional photo of the carbon fiber plastic structure damage. Your appliance on wheels does not impress me.

Well, give me your email address and I will send you a picture of the other side showing how it looks almost perfect too. Furthermore, the parts total so far is very cheap. And if you are really from State Farm, you should already know this. But since the car is so new, I am on the fence of whether I would prefer they just replace the car. On the other hand, I think just about any other small hatchback car would be totaled anyways. So why would this be any different? Of course the i3 absorbed energy under the bumper cover. But the point is, the integrity of the safety shell held up wonderfully. As a matter of fact, the insurance adjuster looked at a picture of the Cadillac, and said he was seen rear seat passengers die in similar size/weight cars as this i3 when they got rear ended.

FYI Jake, Brendan State Farm looked at the car yesterday. He thinks it looks fairly easy to fix. Then after seeing the Cadillac pictures he said “This i3 is built like a tank!”. He said he has seen people rear ended in little hatchbacks killed in an accident like this.

Warren, did your body shop take on the repair. Very curious to see the cost of having the i3 repaired due to this type of accident. I have watched the numerous youtube videos of government testing, but I’m not convinced the i3 will hold up well when subjected to real world accidents verses staged in house testing. Please keep us updated on the progress of the repairs. Your car and photos have been added to the facebook page for i3 vehicles to see if there are others who may have sustained identical damage and their feedback results from insurance companies and whether they were forced to deal with BMW body shops or had the option to choose a local independent body shop.